FIG. 1 shows a schematic view of a conventional flat panel field emission light source comprising a cathode plate module and an anode plate module. The cathode plate module mainly includes a cathode plate 101, a plurality of emitters 103, a plurality of cathode electrodes and a plurality of gate electrodes. The cathode electrodes and a plurality of gate electrodes (not shown in FIG. 1) are formed on the surface of the cathode plate 101. The anode plate module mainly includes a substrate 105, an indium tin oxide (ITO) layer 107 formed on the inner surface of the substrate 105, and a fluorescent layer 109.
Electron beams emitted from the emitters 103 at a low drive voltage, strike the fluorescent layer 109 which is on the top of the ITO layer, and trigger the light source on the fluorescent layer. Passing through the ITO layer 107, the light source is then emitted from the panel surface of the anode plate module.
The research on the lighting efficiency for flat panel field emission light sources is still on its way of evolving. To achieve the need for high luminance, a flat panel field emission light source has to increase the electron beam density as well as the voltage on the anode plate. Increasing the electron beam density degrades the lighting efficiency of the fluorescent layer. The increase of the power also results in undesirable side-effect of heat problem which makes it unsuitable to be used for a flat panel field emission light source.